Highway Runoff Manual
The Highway Runoff Manual (HRM) provides guidance to direct the planning and design of stormwater management facilities for existing and new Washington State highways, rest areas, park-and-ride lots, ferry terminals, and highway maintenance facilities throughout the state. The HRM establishes minimum requirements and provides uniform technical guidance.
Revision History
M 31-16.05 April 2019
Supplement February 2016
M 31-16.04 April 2014
M 31-16.03 November 2011
M 31-16.02 May 2010
June 2008
M 31-16.01 March 2007
2006 October
2006 May
2004 March
1995 February
Slow down on ice and snow.
It's easier to skid or lose control traveling at higher speeds. Give yourself more time to stop.
Carry chains, practice installing them.
Winter conditions could mean chains are required on your route. Practice putting them on your vehicle ahead of time.
Pack your winter car kit.
Carry extra supplies like warm clothing, ice scraper and brush, jumper cables and other emergency items.